It is possible that many of today's foot problems connected with pronation and related strain of the plantar fascia, the foot's connective tissue, stem from the fact that the foot, evolved over literally millions of years of walking on soft earth and has not yet completely adapted to the predominantly hard and flat surfaces of today's floors and pavements. This theory seems to be supported by the fact that most feet, when not weight-bearing, tend to have transverse contours under the metatarsal phalanx (MP) joints, or `ball` substantially raised from the horizontal on the inner side edge or `varus` as opposed to the outer side, or `valgus.` This can be easily observed when sighting by eye along the plantar surface of the ball as against that of the comparatively horizontal bottom surface of the heel when the foot is non-weightbearing. As the ball of the foot rotates inwardly in the shoe from an unweighted tilted state to a weighted, horizontal state on the floor or pavement thereunder, this rotation is often accompanied by an excessive inward rotation of the arch area. This results in undue pronation or flattening thereof with the attendant discomfort, and often orthopedic damages associated therewith.
Past efforts to deal with this problem can be generally divided into four categories. The first includes shoes and/or footbeds non-adjustable contoured in manufacture to better support the bottom of the foot, or portions thereof. Examples of this approach can be found in the footbed products of the Atlantic Thermoplastics of Woonsocket, R.I., which are sold by Florsheim Co. of Chicago, Ill., and others.
The second category includes shoes and/or footbeds custom molded to the foot and non-adjustable thereafter. Examples of these are disclosed in U.S. Pat. Nos. 2,092,909 and 2,092,910 as well as in the custom-manufactured shoes of Tru-Mold.RTM. Shoes, Inc. of Buffalo, N.Y. and others, whereby the shoes are custom molded in manufacture to fit the contours of the client's feet, from a cast, usually plaster, thereof. Similar results are obtained using footbeds and the like, relatively non-adjustable after customizing, including orthotics directly molded to the foot such as those of Orthofeet Orthotic Systems of Hillsdale, N.J. Even the best of such permanent contouring approaches represent less than ideal compromises in that they can not be readily readjusted to the changes in support needs often encountered in the problem foot.
The third category of solutions to these problems include orthotic elements, readjustable generally by experts, i.e. podiatrists or orthopedists working with their own or outside laboratories. Such elements include a wide range of products, such as the PreformS.RTM. from Berkemann Podiatry Products of Mt. Kisco, N.Y., which include orthotics preformed to a preferred average contouring but readjustable in contour by the application of heat and pressure, and/or by the additions of shims or like elements in a procedure known as `posting.` All of such orthotics are designed to be adjusted by a podiatrist or similar specialist having both the tools and experience to do so, rather than by the end user, who usually lacks both. Similar approaches in the prior art also include the flexible inserts disclosed in U.S. Pat. No. 4,439,936. Other somewhat similar approaches include that described in U.S. Pat. No. 3,306,967 in which resinous foams can be formed for use in footbeds or insole inserts requiring temperatures and equipment normally precluding such adjustment by the consumer. Furthermore, even such products on the market that are conceivably wearer-adjustable, provide no means for the normally unskilled wearer to ensure a safe and proper adjustment of the shoe. These products include somewhat readjustable plastic foam based inserts, such as those sold by P.W. Minor & Son, Inc., of Williamsville, N.Y., under the trade names of Minorplast.RTM. and Plastamold.RTM., both designed for adjustment by podiatrist or similar skilled professional, and both somewhat prone to losing at least some of their support characteristics over time. It should also be noted that orthotics requiring adjustment by podiatrists or the like are usually not only relatively expensive, but also frequently necessitate multiple office visits by the wearer to obtain satisfactory results.
The last category of proposed solutions includes adjustable canting means designed for end-user adjustment. This category seems to be limited to downhill or `alpine` skiing applications, wherein a variable transversely rotational axial canting of the foot is used to improve the edge control of the ski. Such products, which include the Flexon.RTM. boots distributed by Raichle Molitor U.S.A. Inc., of Brewster, N.Y., the VX Racer with its adjustable Symflex.RTM. heel device, available from Sanmarco of Italy and others, are designed for use with the currently standard rigid ski boot sole, and as such are not practical for use in general footwear which must flex at least at the ball, during the gait cycle. Likewise, the Nava Skiing System available through Nava Leisure U.S.A., Inc. is also completely impractical for adaptation to general footwear, since it controls leg canting rather than the foot canting required in general shoe applications.
Thus, there still remains a real need for orthotic foot-canting devices that can be adjusted as needed by the end user in a simple and safe manner, preferably but not necessarily under the guidance of podiatrists, trainers or similar specialists.